84 . BIRDS OF TUNISIA 



with rufous ; underparts silvery-white, washed on the sides and flanks with 

 light buff. 



Iris light yellow ; bill light brown above and yellowish below ; feet 

 light yellow. 



Total length 4 inches, wing 2-20, culmen -35, tarsus -75. 



Observation. — The plumage of the only two specimens of this Warbler in 

 my collection is exceedingly pale, but is probably faded, the birds having 

 been obtained in the mouth of July. 



This little Desert-Warbler appears to be the western representa- 

 tive of S. nana (Hemp, and Ehr.), differing from that species in the 

 more rufescent isabelline colour of its plumage, and in its slightly 

 smaller size. It is no doubt a good geographical form, and fully 

 entitled to subspecific distinction, being, indeed, one of the many 

 illustrations we have of the tendency shown by birds, as well as by 

 other members of the fauna and flora of the Sahara region, to assume 

 rufous or isabelline hues, and forming another example of Nature's 

 providential disposition for the preservation of species by protective 

 colouring. 



The species occurs in the more southern and desert districts of the 

 Tunisian and Algerian Sahara, as also in Tripoli, from whence I have 

 specimens in my collection, obtained by Mr. Dodson at Oumsinerma, 

 in the extreme east of the Vilayet. 



Loche seems to have been the first to distinguish the form, 

 meeting with it in Southern Algeria, and describing it as a new 

 species under the name of Stoparola desertii (Rev. et Mag. de Zool., 

 1858, p. 394, pi. 11, fig. 1). 



The Turati Collection of the Milan Museum possesses a specimen 

 of this Warbler, which was obtained by Loche in the Algerian Sahara, 

 and is probably the type of his S. desertii. 



More recently the species has been met with by Dr. Koenig near 

 Dzelfana, El-Alia and El-Mouilah in the Algerian Sahara, and by 

 Baron v. Erlanger on the Djebel Dekanis, Gelb-el-Assued and Bou- 

 Kartuf in the Tunisian Sahara. To both these gentlemen, as well 

 as to Loche, we are indebted for interesting notes regarding the 

 species. 



The Western Desert-Warbler appears to be somewhat local in its 

 distribution, and is nowhere really abundant. It affects sandy 



